Process of making artificial fibers



Patented Feb. 1, 1944 PROCESS OF MAKING ARTIFICIAL mans Erich Graumann and Walther Zetzsche, Premnltz, Germany: vested in the Alien Property Custodian No Drawing. Application January .4, 1941, Serial No. 373,140. In Germany December 11, 1939 6 Claims.' (01. is s4) Our present invention relates to the production of artificial filaments, .fibers or ribbons from cellulose and more particularly to the production of curly filaments and the like. v

In producing artificial filaments and the like, especially staple fibers, it is necessary 'to give the filaments a more or less fine-wavy stable curl, in order to render them wool-like. Not

only is this curl of the artificial filaments of importance for the properties and working up of products unspun, but for the properties and particularly the strength of the yarns spun therefrom. Y 7 Many proposals have been made for curling staple fibers and the like.- However, there is no method which results in products satisfactory in everyrespect. It has, for instance, been proposed to curl the cut fiber by means of liquids intensely moved, for instance, after-treating baths or decomposing baths. It is also possible to press filaments freshly produced and still plastic as well asflnished, for instance, with fluted rolls to form fine waves. Moreover, it has been proposed to give loose fibers a wavy form by a treatment with vapors or by alternately cooling and heating them. Furthermore conof the spinning bath. A process has also been proposed in which filaments of cellulose xanthogenate are converted into cellulosehydrate in hot decomposing liquids without cedure under a stress gradually increasing in several drawing frames, then to deacidify the filaments with stretching at a temperature be tween 90 and 100 C.,-and to cut them into staple fibers in a desulfurizing liquid whereupon they are after-treated in loose form.

as they cause much trouble, in addition the out troublesome steps.

A Iurther object is to provide textile fibers valuable respecting their appearance and working up as well as the properties of the yarns spun therefrom. 4

, following hereinafter.

/ ing some acid and, if desired, salt and the second All these modifications are of disadvantage 45 only water.

In'order to obtain the difference in tension the continuous or cut two-layered filaments are swelled without stretching in preferably hot water, whereby the filaments freshly produced are simultaneously purified. employment of hot water is favorable, because the tensions are more rapidly released in the heat than in the cold. Instead of water there are also used other liquids capable of swelling cellulose, for instance, cold and hot solutions of salts,

alkalies lor'acids, especially solutions or substances capable of chemically acting on .the swelling cellulose, such as. zinc chloride,'-calcium thiocyanate, sodium hydroxide, sodium sulfide or strong sulfuric acid. Steam is also suitable for producing curl. F

It is advantageous to swim the filaments "in a loose condition in the swelling liquids, in order that each filament-can move as freely as possible. An intense moving of the liquids is to be avoided since nubs can be formed upon the. filaments thereby. It is desirable to treat the filaments freshly produced and being still wet in the swelling baths. However, the treatment may also be carried out by causing threads already aftertreated with drawing and dried to swell. In this case the success generally is not great.

Processes, in which filaments spun in acid baths without stretching have been regeneratedwhile strongly stretching, do not yield curl in the filaments on after-treating with swelling agents. The reason resides in the fact that the filaments when treated with the swelling agents have not had the capacity to curl or have not possessed the necessary difference in tension between the outer and the inner layers or the outer layer has been too thick or too thin compared with the inner layer. As we have found, it is necessary that the tendencies to shrink of the two layers are different from each other but approximately equal in strength. It is without difilculty to control the procedures oi the coagulation and regeneration so as to obtain the desired character of curl. The'ripeness of the WS- cose can be chosen for a given effect of coagulation and a certain duration of action in the first bath so, that the filament is regenerated to such an extent after having passed through the first bath and the open air behind it that an approximately equal part, which is regenerated during or after stretching, remains for the inner layer. It is immaterial whether the non-stretched or only slightly stretched outer layer and the stretched inner layer are regenerated in one or several baths. If two baths serve to form the outer layer, the first coagulating bath may contain such substances as convert the surface of the filament only into cellulose xanthogenate. It is of advantage to stretch the inner layer as intensely as possible. The stretching is therefore conveniently carried out in a hot liquid.

When the ripeness and viscosity of the spinning solution are given in the spinning process according to this-invention, the effects of coagulation and regeneration or the duration of action of the baths, 1. e., the acid and salt content and the temperature of the baths, and the length of the paths inbath and air may also be controlled in such a manner that the energies produced in the two layers by releasingthe difierence in tension are different and act against each other, whereby a curl is obtained. The adjustment of the firstbath is considerably facilitated by adding large amounts of salts capable of retarding the decomposition of the filament. There are cations suitable for producing a fine-wavy curl such as zinc, potassium, lithium, ammonium, aluminium, and magnesium. In order to find out a bath containing a favorable combination of acids and salts, it is merely necessary. to place the'spun filaments into hot water and observe the forming curl. By varying the acidity of the first bath and/or the salt content and/or-the period of action of the baths the conditions are quicklydetermined'on which the most suitable curl is produced. A'short-wavy curl is easily "attained by using zinc and/or potassium.

The process of this invention is not only applicable to the production of cellulosehydrate filaments from viscose but to that of artificial filaments from copper hydroxide ammonia solutions. In this case the outer layer may be formed in the spinning funnel without considerably stretching and; the; inner layer subsequently outside the funnel during or after strongly stretching, preferably in hot water which may contain some acid. After the copper has been washed out from the thread, conveniently under stretching, curl is effected by the same means which are used for working up viscose.

For producing curl according to the present invention it is not necessary that the outer cellulosehydrate layer is sharply separated from the inner layer. Several intermediate layers may also be provided.

The more detailed practice of this invention is illustrated by the following examples. There are of course many forms of the invention other than these specific embodiments.

- Example 1 Viscose containing 8% of cellulose and 6.5% of caustic soda with a ripening point of 7 /2 is extruded through a 2500/0.07 nozzleinto a bath containing 7.9% of H2504, and 29.5% of Nazsol and kept at 50 C., the length of immersion being 15 cm., to form a 1.4 denier thread. The bundle of filaments is collected over a guide roller on a drum having a peripheral speed of 33 m./minute and is' continuously transferred through a water bath heated to C. and comprising a length of immersion of lm. to a second drum having a peripheral speed of 55 m./minute. The threads are then sent through a cutting device without stretching. The staple fibers thus obtained are-subsequently treated in a water bath at'80 C., in orderto release" the difierence in tension, and remain therein 'fioating ireefrom one anotheruntil contraction is complete. Finally the staple fibers while conveyed by a band permeable to liquids aresprinkled with solutions suitable for after-treatment without being suspended in the liquids.

I Example 2 Viscose containing 7.7% of cellulose and 6.5%

of caustic soda with a salt point of 7%, is ex truded through a GOO/0.08 nozzle into a bath fibers cut up without tension are then treated;

without being previously dried, with sulfuric acid of 2% strength at 70 .C.to produce curl, are subsequently deacidified' without being suspended in the liquid usedfl then desuliurized,

soaped and finally dri'ed. The fibers exhibit a good short-wavy curl, fa tenacityldryr of 3 grams per denien'a tenacitydwet) of Z grams per denier, and an'elongation of 19%. e

. Example 3:

Viscose containing 7.7% of'cell'ulose enacts, 5 31 of caustics'oda with'a salt-point of 71/;

' denier thread, the length through a water bath I strength at 85 0., whereby fibers thus curled truded through a 2500/0107 con 8.0% to 8180:. 1.8% of ZnSOr and kept at 50' (2., to form a 1,4

of the filaments immersed' being 30 cm. The filament bundle is then collected on a speed of 34. m./minute transferred through a water bath 4 m. in length to a second drum heated at 80 C. and having a peripheral speed of 55 mJminute. The filaments are then cut up without tension and treated with water in a vat at 75 0. The staple and loosened are brought by a conveying band to the several treating baths.

nomleintoabath Example 4 Viscose containing 7.7% of cellulose and 6.5% of caustic soda with a ripen ng point of 6% is extruded through a 2500/0.07 nozzle into a bath containing 8.7% of H2804, 21.6% of NazSOe, 6.5% of (NHQaSOt, and 1.8%,0f ZnSOr, the length of the filaments immersed being 15 cm. The bundle of filaments is collected on 'a drum at the rate of 32 m./minute and transferred 3m in length at 95 C. (while drawn by .a second drum having a peripheral speed of 55 iii/minute. The filament bundle is then cut up and the staple fibers are subsequently treated with sulfuric acid of 1% the curl is released. from acid by washbeing suspended in Finally the fibers are freed ing, after-treated without the used liquids and dried.

Example 7% is extruded through a 2500/0.07 nozzle into a bath containing 7.9% of H2804, 22.3% of M12804, 6.7% of K2804, and 2.4% of ZnSOa and kept atv50 0., to form a 1.4 denier thread, the length of immersion being cm. The thread is collected on a drum having a peripheral speed of 32 m./minute and is transferred through a hot bath 50 cm. in length and containing sulfuric acid of 2% strength and subsequently through a water bath 4 m. in length at 90 C. The filaments are stretched by a second drum with a peripheral speed of 55 m./minute during these two procedures. The bundle is then cut up without drawing and treated with hot water to release the difierence in tension. The staple fibers thus curled and loosened are treated and dried. The resulting fibers exhibit an especially fine" and uniform curl and resemble merino-wool.

Example 6 Viscose containing 7.7% of cellulose and 6.5%. of caustic soda with into a setting bath ontaim'ng 7.9% of H2804. 26.8% of NazSOr and 2.4% of ZnS04 in a manner as described in Example 1. The filament bundle is collected on a drum having a peripheral speed of 33 m./minute and is continuously transferred through a hot bath 2 m. in length and containing sulfuric acid of 2% strength and subsequently through a hot water bath 3 m. in length, the filaments being drawn at the rate of 55 m./minute when treated in the baths. The fixed filament bundle is cut up and then treated in a bath containing a diluted solution 'of Nazism to produce curl. The desulfurization eflected thereby renders the usual desulfurizing stage unnecessary.

27.3% of Na'aSOi and a ms" finally aftera salt point of 1 is spun I of caustic soda with sulfuric acid of 7 Example? Viscose containing 8.0% of cellulose 01' causticisoda with a salt point '0! 7.3 through 9. 600/008 nozzle into a bath containin! 8.8% of H2804, 23.3% of 118280;, 6.2% of H304, and 2.0% Of Z1180; and kept at 50 C. to

and 6.5%

form a 3% denier'thread, the lengthof immer sion being 15 cm. The filament bundle is collected on a drum having a peripheral speed of 29 m./minute and is stretched by a second drum having a peripheral speed of 55 m./minute. Between the two drums the bundle is transferred through a bath 15 cm. in length and containing 2% strength at C. The filaments cut with or-without tension are especially fine-wavy. i

Example 8 Viscose containing 7.4% of cellulose and 6.5% of caustic soda with a ripening point of 7.0 is extruded through 9. 2500/00? nozzle into a bath containing 8.6% of H2804, 24.7% of N82S04 and 5.7% of Al2(S 04)a and kept at 50 C. to form a 1.4 denier thread, the length of immersion being 15 cm. The bundle of filamentscollected at the rate of 36 m./minute is transferred through a water bath 2 m. in length at C. and stretched therein'at the rate of 55 m./minute The filaments now entirely consisting of cellulosehydrate are out whereby the'curl is released The fiber has a tenacity (dry) of 2.1 grams per denier and an elongation of 19% and exhibits a good curl.

Example 9 Viscose containing 7.4% of'cellulose and 6.5% of caustic soda with a ripening point of 7.0 is extruded through a 2500/0.07 nozzle into a bath containing 8.5% of H2804, 24.4% of NazSO; and 6.2% of M8804, to forms. 1.4 denier thread, the

- lengthof immersion being 15 cm. The bundle of Viscose containing 7.7% of cellulose and 6.5% of caustic soda with a salt point of 3.75 is extruded through a 2500/0.07 nozzle into a bath containing 6.5% of H2804, 22.4% of Na2SO4, 6.4% of K1804 and 1.9% of ZnSOr and maintained at 20 C. The bundle of filaments collected at the rate of 45 m./minute is transferred through a bath '1 m. in length and containing sulfuric acid 012% strength and then through a water bath 3 m. in length at 95 0., the bundle being stretched at the rate of 55 m./zninute when treated in the baths. 7 The filaments are then cut .up and treated with'water of 80 C.

Example 11 Viscose containing 8.0% of cellulose and 6.6% a ripening point of 7 is extruded through a 2500/0.07 nozzle into a bath containing 9.2% of H2804, 21.5% of N8.2SO4, 6.6% of K2804. and 2.1% of ZnSO4, to form a 1.6 denier thread, the length of immersion being 15 cm. The bundle of filaments bath 5 m. in length and rate of 55 mJminute.

isext'ruded' and soaked in hot water.

m./minute. The bundle now entirely i collected at the rate of 45 m./minute is transfered through a hot water elongation.

' Example 12 Viscose containing 7.7% of cellulose and 6.5% of caustic soda with a salt point of 7 /4. is'extruded through a GOO/0.08 nozzle into a bath containing 8.2% H2804, 27.8% of 11112304 and 2.1% of ZDSO4 and kept at 50 0., to form a 3.75 denier a high coefficient of described in Example 14 the setting bath con-' tains 9.5% of H2804 instead of 8.3%. However, curl is again produced in this instance, if a jet with 1200 holes, each of 0.07 mm. diameter is d. The path in open air between the acid and the hot water baths is 4 m. inall examples mentioned above; however, the paths may also be shorter or longer, for instance such as -50 cm. or am. If' necessary, a too long path is coma pensated by reducing the concentration of acid thread, the length off immersion-being 15 cm.

The bundle of filaments is collected on a drum having a peripheral speed of 29 m./minute and stretched byya second drum having a peripheral speed of 55 m./ininute. Between the drums the bundle is transferred through a bath 50 cm. in length and containing sulfuric acid of 12% strength at a temperature of 70 C. and subsequently through a water bath 4.80 m. in length and kept at 95 C. The bundle is then treated with water of 80 C. without stretching to release the difference in tension and is subsequently brought to the several after-treating baths likewise without stretching, wherein the treatment is preferably carried out according to the dip-;

ping process.

Example13 Viscose containing 7.7% .of cellulose and 6.5%

'of caustic soda with a salt-point'of 7% is extruded through 9; 2500/1107 nozzle into a bath containing 11.8%v of H2S04, 12.8% 'of Na2S04, 6.3% of K2804, and 1.9% of ZnSOi to form a 1.8 denier thread, thev length of immersion being 10 cm.

in the first path or shortening the bath in the bath.

Example 16 A copper hydroxide ammonia cellulose solution containing 9% of cellulose, 10% of ammonia and 5.4% of copper hydroxide is spun through a nozzle with holes, each of 0.5 mm. diameter into water in the spinning funnel at 30 C. The filament bundle leaving the lower end of the 'funnel is collected in a trough on a drum, the

speed of which corresponds to that of the bundle extruded.- The trough in which the lower part of the funnelimiherses is filled with water from the funnel until the drum. is below the surface of the liquid. The filament bundle is then transferred over a second drum non-driven into The bundle of filaments is collected on a drum having a peripheral speed of 32 m./minute and stretched by a second drum having .a peripheral:

speed of 55 m./i ninute. Between the drums the filaments are transferred through a bath 1 m.

long and containing not sulfuric acid of 2% strength and subsequently through a water bath 5.0 m. long and-kept at 90 C. After the bundle has been cut up the curl is produced and the after-treatment carried out in a manner asdescribed in any of the foregoing examples.

A'similar curl is obtained if the setting bath contains only 10.9% of H2804 instead of 11.8%

' and is 15 cm. long instead of 10 cm. The fibers,

however, do not exhibit curl, if 15% or 16% of H2504 are used instead of 11.8% in the bath.

- Example 14 Viscose containing 7.4% of cellulose and 6.5%

of caustic soda with a ripening point of 6 /2 isextruded through a jet with 60 holes, each of 0.07

mm. diameter into a setting bath contai 8.3% of H2804, 20.3% of M2804 and 4.2% 0 ZnSOr and maintained at 50 C. to form a 2 de-'- nier thread, the length of the thread immersed being 15 cm. The filament bundle is collected on a drum having a peripheral speed of 30 m./minute and is continuously transferred through a bath 1.6 m. in length and consisting of an aqueous solution of 1.5% of H2804, 3.0% of Na2S04 and 0.4% of ZnS04 at 90 0., the stretching being effected by a drum having a peripheral speed-of 56 m./minute. A good. curl is produced by treating the continuous thread a further trough containing sulfuric acid of 2% strength and a temperaturebf 80 C. In this acid trough the bundle is stretched between two or several motor-driven drums, the length of immersion being 2 m. The extent of the stretching thus produced is 25%. The bundle is then cut up and the staple fibers are subsequently treated in a bath with water of 90 0. without stretching and allowed to shrink.

We claim: I

' 1. A process for producing curly filaments, fibers and ribbons from cellulose which comprises, spinning a solution of a cellulosic substance selected from the class consisting of viscose and cuprammonium cellulose into' a precipitating bath without substantial stretching to effect a partial but substantial regeneration of the individual spun bodies to cellulose hydrate completing the regeneration of the individual spunbodies to cellulose hydrate .by subjecting them while strorigly stretching to the action of a hot,

, aqueous regenerating bath thereby forming spun-bodies individually consisting of two layers of cellulose hydrate of slightly unequal tendenstill wet with water of 0. without stretching.

. Example 15 A curl is not attained if in the modification pies to shrink, and subjecting the so treated spun-bodies without stretching to the action ofa swelling agent to curl the same.

2. The process as described in claim 1 in which said cellulosic substance is viscose andsaidprecipitating .bath is a weakly acid aqueous bath.

3. The process as described in claim 1 in which said cellulosic substance is viscose, said precipitating bath is a weakly acid aqueous bath and said regenerating bath is hot water.

4. The process as described inclaim' 1 in which said cellulosic substance is cuprammonium cel-- lulose, the precipitating bath is water and the iegenrating bath is a very weakly acid aqueous ath. I 5. The process as described in claim 1 in which the cellulosic substance is viscose.

6. The process as described in claim 1 in which the cellulosic substance is cuprammonium cellulose.

WALTHER ZETZSCHE. ERICH GRAUMANN. 

